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The study of self-lubricating coatings is a rapidly developing research field that is expected to address major issues arising from operation under high loads and thermal stresses of machine parts. It is of utmost importance that various critical tribological pairs such as crankshaft bearings, piston rings maintain their integrity, thus contributing to the engines efficient and reliable operation for long periods of time. Therefore, a choice of high-strength metals is required, with special treatments and/or coatings in combination with sufficient lubrication. In the present study, liquid lubricants encapsulated in poly(urea-formaldehyde) shells were incorporated in ceramic-metal matrices to produce composite coatings by Atmospheric Plasma Spraying. Aspects concerning the survival of the capsules during their flight through the high temperature plasma flame, the maintenance of their integrity at impact with the substrate with high kinetic energy, their homogeneous dispersion within the coating mass, thermal spray deposition parameters adjustment and optimization are thoroughly discussed. Coating properties such as roughness, friction, adhesion strength, and wear behaviour were also investigated. Microstructural characteristics and friction-wear behaviour were found to be critical to the durability of coating. [ABSTRACT FROM AUTHOR]

Purpose: The aim of the present study was to investigate the association between muscle fiber composition, body composition, resting glycemic–lipidemic blood profiles, in apparently healthy, young, active females. Methods: Thirty-four young healthy female volunteers were allocated into two groups, depending on their Vastus Lateralis type IIx muscle fibers percent cross-sectional area (%CSA; H: high type IIx %CSA; L: low type IIx %CSA). Body composition was determined via dual-energy X-ray absorptiometry. Venous blood samples were collected for the determination of resting serum glucose, Insulin, Apo-A1, HOMA-IR, triglycerides (TG), total cholesterol (TC), High-density lipoprotein (HDL-C), and Low-density lipoprotein (LDL-C) concentrations. Nutritional intake was also evaluated. Results: Individuals of the H group have significantly higher body mass, body fat percentage-mass, and resting blood indices of glycemic and lipidemic profiles, compared to those of L group (p < 0.001). Increased type IIx and low type I, IIa muscle fibers %CSAs were linked with poorer body composition, glycemic and lipidemic blood profiles (r: − 0.722 to 0.740, p < 0.001). Linear regression analyses revealed that the impact of muscle fibers %CSA (B coefficients ranged between − 0.700 and 0.835) on the above parameters, was at least, of the same or even of greater magnitude as that of body composition and daily nutritional intake (B: − 0.700 to 0.666). Conclusion: Increased type IIx and low Type I, IIa %CSAs are associated with poorer body composition and glycemic–lipidemic profiles in young healthy females. The contribution of the muscle fiber %CSA on health status seems to be comparable to that of nutrition and body composition. [ABSTRACT FROM AUTHOR]

Solving large sparse linear systems, efficiently, on supercomputing infrastructures is a time-consuming component for a wide variety of simulation processes. An effective parallel solver should meet the required specifications, concerning both convergence behavior and scalability. Herewith, a class of two-stage algebraic domain decomposition preconditioning schemes based on the upper Schur complement method is proposed, in order to exploit appropriately distributed memory systems with multicore processors. The design of the method has been focused on homogeneous hybrid parallel systems, i.e., distributed and shared memory systems. However, the proposed method can also be applied to heterogeneous systems, such as cloud infrastructures, or hybrid parallel systems with accelerators, by modifying the workload distribution algorithm and taking into account the different network latencies and bandwidths. The first stage of the proposed schemes is related to the assignment of the subdomains among the workstations of the distributed system, whereas the second stage concerns the further redistribution of the subdomains to each core of a processor. The proposed method utilizes multiprojection techniques, based on semi-aggregated subdomains, leading to improved convergence behavior as the number of subdomains increases. Moreover, a subspace compression technique is used, in order to improve the performance of the preprocessing phase and reduce the memory requirements of the proposed scheme. The preconditioning schemes were combined with a parallel Krylov subspace method, i.e., the parallel preconditioned GMRES(m) method. The convergence behavior, the performance and the scalability of the proposed preconditioning schemes are examined and compared to existing state-of-the-art methods, by conducting several numerical experiments on supercomputing infrastructures. [ABSTRACT FROM AUTHOR]

In this paper, new neural network (NN) methods are proposed to forecast intermittent demand and we empirically study their performance as compared to parametric and non-parametric forecasting methods proposed in the literature. The empirical investigation uses demand data for 5,135 spare parts for the fleet of aircrafts of an airline company. Three parametric benchmark methods are examined: single exponential smoothing (SES), Croston's method and Syntetos–Boylan approximation, along with two bootstrapping methods: Willemain's method and Zhou and Viswanathan's method. The benchmark NN method considered in this paper is that proposed by Gutierrez et al. (2008) The paper shows the outperformance of SES and the NN methods for (a) their forecast accuracy and (b) their inventory efficiency (trade-off between holding volumes and backordering volumes) when compared to the other methods. Moreover, among the NN methods, a new proposed method is shown to be better than that proposed by Gutierrez et al. in terms of forecast accuracy and inventory efficiency. [ABSTRACT FROM AUTHOR]

A class of novel parallel preconditioning schemes in conjunction with a Krylov subspace iterative method for solving general sparse linear systems is presented. The proposed preconditioning schemes are domain decomposition methods that enforce the continuity of the solution on the subdomain interfaces using Lagrange multipliers, without requiring geometric information, namely algebraic tearing and interconnecting methods. Hence, they are applicable to a wide variety of problems as they are based only on the adjacency graph corresponding to the coefficient matrix. A modification of the proposed schemes, which improves performance while reducing the required operations is also presented. The algebraic tearing and interconnecting methods are designed for distributed systems with multicore nodes. Numerical results concerning the convergence behavior and the parallel performance of the proposed schemes are given along with discussions. [ABSTRACT FROM AUTHOR]

In this paper, a model of a discrete material flow line consisting of three unreliable machines and one buffer of limited capacity is analysed. A similar system, but with continuous flow of material was examined by Helber and Mehrtens (2001) and Tan (2001). In our system it is assumed that the buffer has two immediate preceding machines, performing the same operations and one immediate succeeding machine that receives material from the buffer. For the case where the buffer reaches its own capacity, one of the two preceding machines has priority over the other to dispose its processed part into the buffer. Processing times are assumed to be deterministic and identical for all machines and are taken as the time unit. Geometrically distributed operation dependent failures at the machines are assumed. All possible transition equations for the examined model are derived and a recursive algorithm that generates the transition matrix for any value N of the storage level is developed. Once the transition matrix is known the performance measures of the model under consideration can be easily evaluated. This model may be used as a building block in a decomposition method to evaluate large production systems with split/merge operations (for example, flow lines with quality inspections and rework loops). [ABSTRACT FROM AUTHOR]

We present a robust generalized queuing network algorithm as an evaluative procedure for optimizing production line configurations using simulated annealing. We compare the results obtained with our algorithm to those of other studies and find some interesting similarities but also striking differences between them in the allocation of buffers, numbers of servers, and their service rates. While context dependent, these patterns of allocation are one of the most important insights which emerge in solving very long production lines. The patterns, however, are often counter-intuitive, which underscores the difficulty of the problem we address. The most interesting feature of our optimization procedure is its bounded execution time, which makes it viable for optimizing very long production line configurations. Based on the bounded execution time property, we have optimized configurations of up to 60 stations with 120 buffers and servers in less than five hours of CPU time. [ABSTRACT FROM AUTHOR]

A hybrid approach for the solution of linear elliptic PDEs, based on the unified transform method in conjunction with domain decomposition techniques, is introduced. Given a well-posed boundary value problem, the proposed methodology relies on the derivation of an approximate global relation, which is an equation that couples the finite Fourier transforms of all the boundary values. The computational domain is hierarchically decomposed into several nonoverlapping subdomains; for each of those subdomains, a unique approximate global relation is derived. Then, by introducing a modified Dirichlet-to-Neumann iterative algorithm, it is possible to compute the solution and its normal derivative at the resulting interfaces. By considering several hierarchical levels, higher spatial resolution can be achieved. There are three main advantages associated with the proposed approach. First, since the unified transform is a boundary-based technique, the interior of each subdomain does not need to be discretized; thus, no mesh generation is required. Additionally, the Dirichlet and Neumann values can be computed on the interfaces with high accuracy, using a collocation technique in the complex Fourier plane. Finally, the interface values at each hierarchical level can be computed in parallel by considering a quadtree decomposition in conjunction with the iterative Dirichlet-to-Neumann algorithm. The proposed methodology is analysed both regarding implementation details and computational complexity. Moreover, numerical results are presented, assessing the performance of the solver. [ABSTRACT FROM AUTHOR]

Libya is following the trend observed in developing countries of steadily becoming more obese, such that obesity in Libya has reached epidemic proportions in the twenty-first century. The prevalence of obesity in Libya has more than doubled in the last three decades, with the numbers of overweight and obese adults being continuing to grow. Therefore, this study aimed to estimate and describe the prevalence of overweight and obesity among Libyan men and women. A cross-sectional survey was conducted to examine the prevalence of overweight and obesity among the Libyan population. A multistage sampling technique was employed to select 401 Libyan adults randomly from the Benghazi electoral register. Qualified nurses were allocated to take anthropometric measurements (including visceral fat and Body Mass Index (BMI)) from participants using the Segmental Body Composition Analyser and a portable Stadiometer. The response rate achieved in this cross-sectional study was 78%. Four hundred and one Libyan adult, aged 20-65 years, participated; 253 were female (63%). The prevalence of obesity, overweight, and normal weight among Libyan adults was 42.4%, 32.9%, and 24.7%, respectively. The results also revealed that approximately 75.3% of Libyan adults were overweight and obese, and the prevalence of overweight and obesity in women was significantly higher than that in men (the prevalence of overweight was 33.2% in women compared to 32.4% in men, while the prevalence of obesity was 47.4% in women compared to 33.8% in men, respectively). The findings of this study confirmed that obesity and overweight are the fastest growing issues and have become one of the most serious public health challenges confronting the Libyan authorities. As the obesity epidemic in Libya continues to escalate, with a complete absence of prevention interventions to reduce obesity, more research is desperately needed to follow the trend of gender difference in the prevalence of overweight and obesity among Libyans adults across the Libyan state to improve the effective interventions for preventing obesity. [ABSTRACT FROM AUTHOR]

Presents a study on the conductivity of tin oxide thin films produced by reactive direct current sputtering in various oxygen flow in zero grade air as well as in carbon monoxide and ethanol ambient. Experimental techniques; Results and discussion; Conclusions.

Previous work has demonstrated a “side-effect effect,” such that intentionality is more likely to be attributed to agents who bring about negatively valenced as opposed to positively valenced side effects. The rational-scientist model explains this by suggesting that norm-violating side effects are more informative for inferring intentionality than norm-conforming side effects. In the present study we reexamined this account, addressing limitations of previous empirical tests (e.g., Uttich & Lombrozo, Cognition 116: 87-100, 2010). Side-effect valence and norm status were manipulated factorially, enabling an examination of the impact of norm status on intentionality judgments in both positively and negatively valenced side effects. Additionally, the impact of side-effect norm status on the perceived valences of side effects and agents was examined. Effects of norm status were found for both positive and negative side effects. Violation of an ostensibly neutral norm led to negative perceptions of the side effect. However, a norm status effect on intentionality judgments persisted when these effects were controlled. These results support the view that the side-effect effect is the result of the rational use of social-cognitive evidence. [ABSTRACT FROM AUTHOR]

A hybrid parallel self mesh-adaptive N-body method based on approximate inverses and multiprojection techniques is proposed. This method is a three-dimensional hybrid parallel mesh-type N-body scheme based on the solution of the Poisson equation in the physical space with boundary conditions obtained from multipole expansion formulas. In order to improve the accuracy of the solution, especially in shallow regions, a self mesh-adaptive scheme is used to create a hierarchy of independent smaller N-body problems. The parallelization of the scheme is based on a uniform partitioning of the bodies with respect to available computer nodes, and communications are required only for the computation of the density and potential distributions. The proposed scheme is suitable for large-scale galaxy simulations with millions of bodies on high-resolution meshes, for distributed HPC systems with multicore computer nodes. Moreover, large-scale galaxy simulations are performed on modern Cloud environments in order to examine the applicability and performance. Implementation issues concerning the proposed scheme are also discussed. The parallel performance and speedup of the hybrid parallel N-body method on HPC systems as well as on Cloud environments are presented and discussed. [ABSTRACT FROM AUTHOR]

A new parallel Self Mesh-Adaptive N-body method based on approximate inverses is proposed. The scheme is a three-dimensional Cartesian-based method that solves the Poisson equation directly in physical space, using modified multipole expansion formulas for the boundary conditions. Moreover, adaptive-mesh techniques are utilized to form a class of separate smaller n-body problems that can be solved in parallel and increase the total resolution of the system. The solution method is based on multigrid method in conjunction with the symmetric factored approximate sparse inverse matrix as smoother. The design of the parallel Self Mesh-Adaptive method along with discussion on implementation issues for shared memory computer systems is presented. The new parallel method is evaluated through a series of benchmark simulations using N-body models of isolated galaxies or galaxies interacting with dwarf companions. Furthermore, numerical results on the performance and the speedups of the scheme are presented. [ABSTRACT FROM AUTHOR]

The inferior vena cava, also known as the posterior vena cava, is the large vein that carries de-oxygenated blood from the lower half of the body into the right atrium of the heart. Congenital anomalies of the inferior vena cava result from the persistence of the embryonic venous system. The majority of cases are clinically silent and are diagnosed in routine dissection studies, in retroperitoneal surgeries, or through imaging for other reasons. Although these anomalies are rare, they are of great importance during operations in the abdominal area or in the treatment of thromboembolic diseases. We report two cases of double vena cava and left vena cava, respectively, and a short review of the relevant literature. [ABSTRACT FROM AUTHOR]

Empirical, hypothesis-driven, experimentation is at the heart of the scientific discovery process and has become commonplace in human-factors related fields. To enable the integration of visual analytics in such experiments, we introduce VEEVVIE, the Visual Explorer for Empirical Visualization, VR and Interaction Experiments. VEEVVIE is comprised of a back-end ontology which can model several experimental designs encountered in these fields. This formalization allows VEEVVIE to capture experimental data in a query-able form and makes it accessible through a front-end interface. This front-end offers several multi-dimensional visualization widgets with built-in filtering and highlighting functionality. VEEVVIE is also expandable to support custom experimental measurements and data types through a plug-in visualization widget architecture. We demonstrate VEEVVIE through several case studies of visual analysis, performed on the design and data collected during an experiment on the scalability of high-resolution, immersive, tiled-display walls. [ABSTRACT FROM AUTHOR]

During the last decades, Multigrid methods have been extensively used for solving large sparse linear systems. Considering their efficiency and the convergence behavior, Multigrid methods are used in many scientific fields as solvers or preconditioners. Herewith, we propose two hybrid parallel algorithms for N-Body simulations using the Particle Mesh method and the Particle Particle Particle Mesh method, respectively, based on the V-Cycle Multigrid method in conjunction with Generic Approximate Sparse Inverses. The N-Body problem resides in a three-dimensional torus space, and the bodies are subject only to gravitational forces. In each time step of the above methods, a large sparse linear system is solved to compute the gravity potential at each nodal point in order to interpolate the solution to each body. Then the Velocity Verlet method is used to compute the new position and velocity from the acceleration of each respective body. Moreover, a parallel Multigrid algorithm, with a truncated approach in the levels computed in parallel, is proposed for solving large linear systems. Furthermore, parallel results are provided indicating the efficiency of the proposed Multigrid N-Body scheme. Theoretical estimates for the complexity of the proposed simulation schemes are provided. [ABSTRACT FROM AUTHOR]

Accessible summary The study aimed to examine the occurrence and type of mental illness stigma that exists in the Greek culture., One hundred and eleven individuals who viewed themselves as belonging to the Greek culture completed a questionnaire that measured different types of stigma and their level. These people lived in either England or Greece., Overall, the Greek people sampled in our survey were found to possess medium-high level of authoritarian attitudes (the view that people with mental illness are inferior) and a moderate level of social restrictiveness (the view that they should be restricted and carefully controlled in society). The results also found a high 'benevolence' score, which indicates that they are also sympathetic to people with mental illness. Greeks educated in England (instead of Greece), who were more religious, who had less knowledge about mental illness and less personal experience of mental illness were most likely to hold stigmatizing attitudes., The results - which support previous research - show that Greek people are sympathetic towards the mentally ill but nevertheless feel the need for them to be closely controlled in society. This means that more work is needed to help minimize negative attitudes among Greek people., Abstract Mental illness stigma negatively affects the lives of individuals with mental health disorders. Studies have indicated that the type and degree of stigma significantly varies across cultures. This study aimed to add to this body of knowledge by examining the prevalence and the type of mental illness stigma among individuals who identified themselves as Greek. It also examined the influence of a range of potential within-culture stigma moderating factors, including levels of previous experience with mental illness and mental illness knowledge. A cross-sectional quantitative design was employed, and 111 participants living in England and Greece were sampled through the snowball sampling technique. Stigma prevalence was measured using the ' Community Attitudes to Mental Illness' questionnaire. The findings revealed that participants showed a high degree of sympathy for people with mental illness but also considered them to be inferior and of a lower social class, and needing strict societal control. Higher stigma was significantly associated with being educated in England (instead of Greece), higher religiosity, lower knowledge levels and lower levels personal experience of mental illness. Targeted antistigma campaigns specifically tailored for the Greek culture are required in order to help reduce stigmatizing attitudes. [ABSTRACT FROM AUTHOR]